Hi Chris
1 Yes they are easy to use
2 They use USB to connect to the computer, and then use your C-Map card that you have in your chartplotter. Get a user card so you can transfer the routes that you create, back to your chartplotter in the boat.
3 I have not found any bad points
4 I bought mine from Fishon Marine --no problems very smooth transaction
5 Just check your model before you purchase, but I think you would be fine.